1menu "Kernel hacking" 2 3source "lib/Kconfig.debug" 4 5config STRICT_DEVMEM 6 bool "Filter access to /dev/mem" 7 depends on MMU 8 ---help--- 9 If this option is disabled, you allow userspace (root) access to all 10 of memory, including kernel and userspace memory. Accidental 11 access to this is obviously disastrous, but specific access can 12 be used by people debugging the kernel. 13 14 If this option is switched on, the /dev/mem file only allows 15 userspace access to memory mapped peripherals. 16 17 If in doubt, say Y. 18 19# RMK wants arm kernels compiled with frame pointers or stack unwinding. 20# If you know what you are doing and are willing to live without stack 21# traces, you can get a slightly smaller kernel by setting this option to 22# n, but then RMK will have to kill you ;). 23config FRAME_POINTER 24 bool 25 depends on !THUMB2_KERNEL 26 default y if !ARM_UNWIND || FUNCTION_GRAPH_TRACER 27 help 28 If you say N here, the resulting kernel will be slightly smaller and 29 faster. However, if neither FRAME_POINTER nor ARM_UNWIND are enabled, 30 when a problem occurs with the kernel, the information that is 31 reported is severely limited. 32 33config ARM_UNWIND 34 bool "Enable stack unwinding support (EXPERIMENTAL)" 35 depends on AEABI && EXPERIMENTAL 36 default y 37 help 38 This option enables stack unwinding support in the kernel 39 using the information automatically generated by the 40 compiler. The resulting kernel image is slightly bigger but 41 the performance is not affected. Currently, this feature 42 only works with EABI compilers. If unsure say Y. 43 44config OLD_MCOUNT 45 bool 46 depends on FUNCTION_TRACER && FRAME_POINTER 47 default y 48 49config DEBUG_USER 50 bool "Verbose user fault messages" 51 help 52 When a user program crashes due to an exception, the kernel can 53 print a brief message explaining what the problem was. This is 54 sometimes helpful for debugging but serves no purpose on a 55 production system. Most people should say N here. 56 57 In addition, you need to pass user_debug=N on the kernel command 58 line to enable this feature. N consists of the sum of: 59 60 1 - undefined instruction events 61 2 - system calls 62 4 - invalid data aborts 63 8 - SIGSEGV faults 64 16 - SIGBUS faults 65 66# These options are only for real kernel hackers who want to get their hands dirty. 67config DEBUG_LL 68 bool "Kernel low-level debugging functions (read help!)" 69 depends on DEBUG_KERNEL 70 help 71 Say Y here to include definitions of printascii, printch, printhex 72 in the kernel. This is helpful if you are debugging code that 73 executes before the console is initialized. 74 75 Note that selecting this option will limit the kernel to a single 76 UART definition, as specified below. Attempting to boot the kernel 77 image on a different platform *will not work*, so this option should 78 not be enabled for kernels that are intended to be portable. 79 80choice 81 prompt "Kernel low-level debugging port" 82 depends on DEBUG_LL 83 84 config AT91_DEBUG_LL_DBGU0 85 bool "Kernel low-level debugging on rm9200, 9260/9g20, 9261/9g10 and 9rl" 86 depends on HAVE_AT91_DBGU0 87 88 config AT91_DEBUG_LL_DBGU1 89 bool "Kernel low-level debugging on 9263 and 9g45" 90 depends on HAVE_AT91_DBGU1 91 92 config DEBUG_CLPS711X_UART1 93 bool "Kernel low-level debugging messages via UART1" 94 depends on ARCH_CLPS711X 95 help 96 Say Y here if you want the debug print routines to direct 97 their output to the first serial port on these devices. 98 99 config DEBUG_CLPS711X_UART2 100 bool "Kernel low-level debugging messages via UART2" 101 depends on ARCH_CLPS711X 102 help 103 Say Y here if you want the debug print routines to direct 104 their output to the second serial port on these devices. 105 106 config DEBUG_DAVINCI_DA8XX_UART1 107 bool "Kernel low-level debugging on DaVinci DA8XX using UART1" 108 depends on ARCH_DAVINCI_DA8XX 109 help 110 Say Y here if you want the debug print routines to direct 111 their output to UART1 serial port on DaVinci DA8XX devices. 112 113 config DEBUG_DAVINCI_DA8XX_UART2 114 bool "Kernel low-level debugging on DaVinci DA8XX using UART2" 115 depends on ARCH_DAVINCI_DA8XX 116 help 117 Say Y here if you want the debug print routines to direct 118 their output to UART2 serial port on DaVinci DA8XX devices. 119 120 config DEBUG_DAVINCI_DMx_UART0 121 bool "Kernel low-level debugging on DaVinci DMx using UART0" 122 depends on ARCH_DAVINCI_DMx 123 help 124 Say Y here if you want the debug print routines to direct 125 their output to UART0 serial port on DaVinci DMx devices. 126 127 config DEBUG_DAVINCI_TNETV107X_UART1 128 bool "Kernel low-level debugging on DaVinci TNETV107x using UART1" 129 depends on ARCH_DAVINCI_TNETV107X 130 help 131 Say Y here if you want the debug print routines to direct 132 their output to UART1 serial port on DaVinci TNETV107X 133 devices. 134 135 config DEBUG_DC21285_PORT 136 bool "Kernel low-level debugging messages via footbridge serial port" 137 depends on FOOTBRIDGE 138 help 139 Say Y here if you want the debug print routines to direct 140 their output to the serial port in the DC21285 (Footbridge). 141 142 config DEBUG_FOOTBRIDGE_COM1 143 bool "Kernel low-level debugging messages via footbridge 8250 at PCI COM1" 144 depends on FOOTBRIDGE 145 help 146 Say Y here if you want the debug print routines to direct 147 their output to the 8250 at PCI COM1. 148 149 config DEBUG_HIGHBANK_UART 150 bool "Kernel low-level debugging messages via Highbank UART" 151 depends on ARCH_HIGHBANK 152 help 153 Say Y here if you want the debug print routines to direct 154 their output to the UART on Highbank based devices. 155 156 config DEBUG_IMX1_UART 157 bool "i.MX1 Debug UART" 158 depends on SOC_IMX1 159 help 160 Say Y here if you want kernel low-level debugging support 161 on i.MX1. 162 163 config DEBUG_IMX23_UART 164 bool "i.MX23 Debug UART" 165 depends on SOC_IMX23 166 help 167 Say Y here if you want kernel low-level debugging support 168 on i.MX23. 169 170 config DEBUG_IMX25_UART 171 bool "i.MX25 Debug UART" 172 depends on SOC_IMX25 173 help 174 Say Y here if you want kernel low-level debugging support 175 on i.MX25. 176 177 config DEBUG_IMX21_IMX27_UART 178 bool "i.MX21 and i.MX27 Debug UART" 179 depends on SOC_IMX21 || SOC_IMX27 180 help 181 Say Y here if you want kernel low-level debugging support 182 on i.MX21 or i.MX27. 183 184 config DEBUG_IMX28_UART 185 bool "i.MX28 Debug UART" 186 depends on SOC_IMX28 187 help 188 Say Y here if you want kernel low-level debugging support 189 on i.MX28. 190 191 config DEBUG_IMX31_IMX35_UART 192 bool "i.MX31 and i.MX35 Debug UART" 193 depends on SOC_IMX31 || SOC_IMX35 194 help 195 Say Y here if you want kernel low-level debugging support 196 on i.MX31 or i.MX35. 197 198 config DEBUG_IMX51_UART 199 bool "i.MX51 Debug UART" 200 depends on SOC_IMX51 201 help 202 Say Y here if you want kernel low-level debugging support 203 on i.MX51. 204 205 config DEBUG_IMX50_IMX53_UART 206 bool "i.MX50 and i.MX53 Debug UART" 207 depends on SOC_IMX50 || SOC_IMX53 208 help 209 Say Y here if you want kernel low-level debugging support 210 on i.MX50 or i.MX53. 211 212 config DEBUG_IMX6Q_UART2 213 bool "i.MX6Q Debug UART2" 214 depends on SOC_IMX6Q 215 help 216 Say Y here if you want kernel low-level debugging support 217 on i.MX6Q UART2. This is correct for e.g. the SabreLite 218 board. 219 220 config DEBUG_IMX6Q_UART4 221 bool "i.MX6Q Debug UART4" 222 depends on SOC_IMX6Q 223 help 224 Say Y here if you want kernel low-level debugging support 225 on i.MX6Q UART4. 226 227 config DEBUG_MMP_UART2 228 bool "Kernel low-level debugging message via MMP UART2" 229 depends on ARCH_MMP 230 help 231 Say Y here if you want kernel low-level debugging support 232 on MMP UART2. 233 234 config DEBUG_MMP_UART3 235 bool "Kernel low-level debugging message via MMP UART3" 236 depends on ARCH_MMP 237 help 238 Say Y here if you want kernel low-level debugging support 239 on MMP UART3. 240 241 config DEBUG_MSM_UART1 242 bool "Kernel low-level debugging messages via MSM UART1" 243 depends on ARCH_MSM7X00A || ARCH_MSM7X30 || ARCH_QSD8X50 244 help 245 Say Y here if you want the debug print routines to direct 246 their output to the first serial port on MSM devices. 247 248 config DEBUG_MSM_UART2 249 bool "Kernel low-level debugging messages via MSM UART2" 250 depends on ARCH_MSM7X00A || ARCH_MSM7X30 || ARCH_QSD8X50 251 help 252 Say Y here if you want the debug print routines to direct 253 their output to the second serial port on MSM devices. 254 255 config DEBUG_MSM_UART3 256 bool "Kernel low-level debugging messages via MSM UART3" 257 depends on ARCH_MSM7X00A || ARCH_MSM7X30 || ARCH_QSD8X50 258 help 259 Say Y here if you want the debug print routines to direct 260 their output to the third serial port on MSM devices. 261 262 config DEBUG_MSM8660_UART 263 bool "Kernel low-level debugging messages via MSM 8660 UART" 264 depends on ARCH_MSM8X60 265 select MSM_HAS_DEBUG_UART_HS 266 help 267 Say Y here if you want the debug print routines to direct 268 their output to the serial port on MSM 8660 devices. 269 270 config DEBUG_MSM8960_UART 271 bool "Kernel low-level debugging messages via MSM 8960 UART" 272 depends on ARCH_MSM8960 273 select MSM_HAS_DEBUG_UART_HS 274 help 275 Say Y here if you want the debug print routines to direct 276 their output to the serial port on MSM 8960 devices. 277 278 config DEBUG_MVEBU_UART 279 bool "Kernel low-level debugging messages via MVEBU UART" 280 depends on ARCH_MVEBU 281 help 282 Say Y here if you want kernel low-level debugging support 283 on MVEBU based platforms. 284 285 config DEBUG_PICOXCELL_UART 286 depends on ARCH_PICOXCELL 287 bool "Use PicoXcell UART for low-level debug" 288 help 289 Say Y here if you want kernel low-level debugging support 290 on PicoXcell based platforms. 291 292 config DEBUG_REALVIEW_STD_PORT 293 bool "RealView Default UART" 294 depends on ARCH_REALVIEW 295 help 296 Say Y here if you want the debug print routines to direct 297 their output to the serial port on RealView EB, PB11MP, PBA8 298 and PBX platforms. 299 300 config DEBUG_REALVIEW_PB1176_PORT 301 bool "RealView PB1176 UART" 302 depends on MACH_REALVIEW_PB1176 303 help 304 Say Y here if you want the debug print routines to direct 305 their output to the standard serial port on the RealView 306 PB1176 platform. 307 308 config DEBUG_S3C_UART0 309 depends on PLAT_SAMSUNG 310 bool "Use S3C UART 0 for low-level debug" 311 help 312 Say Y here if you want the debug print routines to direct 313 their output to UART 0. The port must have been initialised 314 by the boot-loader before use. 315 316 The uncompressor code port configuration is now handled 317 by CONFIG_S3C_LOWLEVEL_UART_PORT. 318 319 config DEBUG_S3C_UART1 320 depends on PLAT_SAMSUNG 321 bool "Use S3C UART 1 for low-level debug" 322 help 323 Say Y here if you want the debug print routines to direct 324 their output to UART 1. The port must have been initialised 325 by the boot-loader before use. 326 327 The uncompressor code port configuration is now handled 328 by CONFIG_S3C_LOWLEVEL_UART_PORT. 329 330 config DEBUG_S3C_UART2 331 depends on PLAT_SAMSUNG 332 bool "Use S3C UART 2 for low-level debug" 333 help 334 Say Y here if you want the debug print routines to direct 335 their output to UART 2. The port must have been initialised 336 by the boot-loader before use. 337 338 The uncompressor code port configuration is now handled 339 by CONFIG_S3C_LOWLEVEL_UART_PORT. 340 341 config DEBUG_SOCFPGA_UART 342 depends on ARCH_SOCFPGA 343 bool "Use SOCFPGA UART for low-level debug" 344 help 345 Say Y here if you want kernel low-level debugging support 346 on SOCFPGA based platforms. 347 348 config DEBUG_VEXPRESS_UART0_DETECT 349 bool "Autodetect UART0 on Versatile Express Cortex-A core tiles" 350 depends on ARCH_VEXPRESS && CPU_CP15_MMU 351 help 352 This option enables a simple heuristic which tries to determine 353 the motherboard's memory map variant (original or RS1) and then 354 choose the relevant UART0 base address. 355 356 Note that this will only work with standard A-class core tiles, 357 and may fail with non-standard SMM or custom software models. 358 359 config DEBUG_VEXPRESS_UART0_CA9 360 bool "Use PL011 UART0 at 0x10009000 (V2P-CA9 core tile)" 361 depends on ARCH_VEXPRESS 362 help 363 This option selects UART0 at 0x10009000. Except for custom models, 364 this applies only to the V2P-CA9 tile. 365 366 config DEBUG_VEXPRESS_UART0_RS1 367 bool "Use PL011 UART0 at 0x1c090000 (RS1 complaint tiles)" 368 depends on ARCH_VEXPRESS 369 help 370 This option selects UART0 at 0x1c090000. This applies to most 371 of the tiles using the RS1 memory map, including all new A-class 372 core tiles, FPGA-based SMMs and software models. 373 374 config DEBUG_LL_UART_NONE 375 bool "No low-level debugging UART" 376 depends on !ARCH_MULTIPLATFORM 377 help 378 Say Y here if your platform doesn't provide a UART option 379 below. This relies on your platform choosing the right UART 380 definition internally in order for low-level debugging to 381 work. 382 383 config DEBUG_ICEDCC 384 bool "Kernel low-level debugging via EmbeddedICE DCC channel" 385 help 386 Say Y here if you want the debug print routines to direct 387 their output to the EmbeddedICE macrocell's DCC channel using 388 co-processor 14. This is known to work on the ARM9 style ICE 389 channel and on the XScale with the PEEDI. 390 391 Note that the system will appear to hang during boot if there 392 is nothing connected to read from the DCC. 393 394 config DEBUG_SEMIHOSTING 395 bool "Kernel low-level debug output via semihosting I/O" 396 help 397 Semihosting enables code running on an ARM target to use 398 the I/O facilities on a host debugger/emulator through a 399 simple SVC call. The host debugger or emulator must have 400 semihosting enabled for the special svc call to be trapped 401 otherwise the kernel will crash. 402 403 This is known to work with OpenOCD, as well as 404 ARM's Fast Models, or any other controlling environment 405 that implements semihosting. 406 407 For more details about semihosting, please see 408 chapter 8 of DUI0203I_rvct_developer_guide.pdf from ARM Ltd. 409 410endchoice 411 412config DEBUG_LL_INCLUDE 413 string 414 default "debug/icedcc.S" if DEBUG_ICEDCC 415 default "debug/highbank.S" if DEBUG_HIGHBANK_UART 416 default "debug/mvebu.S" if DEBUG_MVEBU_UART 417 default "debug/picoxcell.S" if DEBUG_PICOXCELL_UART 418 default "debug/socfpga.S" if DEBUG_SOCFPGA_UART 419 default "debug/vexpress.S" if DEBUG_VEXPRESS_UART0_DETECT || \ 420 DEBUG_VEXPRESS_UART0_CA9 || DEBUG_VEXPRESS_UART0_RS1 421 default "mach/debug-macro.S" 422 423config EARLY_PRINTK 424 bool "Early printk" 425 depends on DEBUG_LL 426 help 427 Say Y here if you want to have an early console using the 428 kernel low-level debugging functions. Add earlyprintk to your 429 kernel parameters to enable this console. 430 431config OC_ETM 432 bool "On-chip ETM and ETB" 433 depends on ARM_AMBA 434 help 435 Enables the on-chip embedded trace macrocell and embedded trace 436 buffer driver that will allow you to collect traces of the 437 kernel code. 438 439config ARM_KPROBES_TEST 440 tristate "Kprobes test module" 441 depends on KPROBES && MODULES 442 help 443 Perform tests of kprobes API and instruction set simulation. 444 445config PID_IN_CONTEXTIDR 446 bool "Write the current PID to the CONTEXTIDR register" 447 depends on CPU_COPY_V6 448 help 449 Enabling this option causes the kernel to write the current PID to 450 the PROCID field of the CONTEXTIDR register, at the expense of some 451 additional instructions during context switch. Say Y here only if you 452 are planning to use hardware trace tools with this kernel. 453 454endmenu 455